Fur trade? Western fur trade rendezvous period (1825 - 1840)? Western fur trade prior to 1825? Eastern fur trade prior to that? I know some guys who still bring in a little money trapping, and generally carry a modern gun when making their rounds.
I'm a reenactor of the western fur trade, rendezvous period. At some events I've carried my northwest trade gun, but mostly I carry my .50 caliber southern mountain rifle which is based on guns from the late flint period. Carrying a southern gun in the western fur trade would indicate that it was a personal arm that I brought with me. My persona is that of a hunter for the fur brigade. I would have made the trip out west with the brigade, and returned again to St. Louis, having contracted my services for wages. I know how to trap beaver, but it's not my thing. I put meat on the family table, for the first time, when I was about ten years old. I wouldn't call myself a serious hunter any more, but I still love it. So that persona fits me. Not as sexy as being a free trapper... but someone's gotta feed the brigade, right?
At .50 caliber, my gun would be on the small side for the job, but not unheard of. The trade gun would be more appropriate; but i like my southern gun better. I like looking at it, carrying it, and holding it. And I built it from a blank, so it's hand made... and I like that about it too. My trade gun was assembled from a kit.
It depends on what and who you're portraying. It's based on research, but it's still fantasy. Grown men dreaming of a life they'll never have and things they'll never do. That's why gunsmiths and builders (like me) put the artifice of aging on our guns; to make them look like they have a history that they don't. In the fur trade all guns were made by hand... but that's not an option for everyone.
The quality and beauty of a well assembled and finished gun from Kibler (and some others) cannot be argued, and will outlast us all when properly used and cared for. When you look at the different finished Kibler guns, I imagine there's one that appeals to you more than the others. That's the one I would recommend. It all depends on who we are, I guess. A good flintlock is magic for me. I'm a flintlock shooter first, and a reenactor second. Reenacting is great fun. And it gives me some connection with my ancestors, who were pioneers, both the east and west. But it's still fantasy. Shooting on the range or at a gathering, carrying your gun while hunting, and taking game... that's reality. That means something today. Pick the one you want. Pick the one you'll use.
I'm older now, than I used to be... so I'm allowed to ramble. For what it's worth.